Remove Line Endings From a File on Linux

Line endings are special characters that mark the end of a line in a text file. On Unix-based systems like Linux, the line ending is represented by a single newline character (
). On Windows, the line ending is represented by a combination of a carriage return (\r) and a newline character (
), which is referred to as CRLF.

Sometimes, you may need to remove line endings from a file for various reasons. For example, you may want to remove line endings before using it as input to a command that expects a single line of input, or to make it easier to process the file in certain applications.

In this article, we will explore how to remove line endings from a file on Linux using several command-line tools.

Removing Line Endings Using tr Command

The tr command is a utility that allows you to translate or delete characters from a file or standard input. To remove line endings from a file using tr, use the following command

tr -d '
' < input_file > output_file

This command reads the input_file, removes all newline characters, and writes the result to output_file. The -d option tells tr to delete the specified characters.

Here's an example of using tr to remove line endings from a file

$ cat input_file
Line 1
Line 2
Line 3

$ tr -d '
' < input_file > output_file

$ cat output_file
Line 1Line 2Line 3

As you can see, the line endings in the input_file have been removed and the resulting text is now a single line in the output_file.

Removing Line Endings Using sed Command

The sed command is a powerful utility for editing text files. It can be used to delete or replace specific patterns in a file. To remove line endings from a file using sed, use the following command

sed ':a;N;$!ba;s/
//g' input_file > output_file

This command reads the input_file, removes all newline characters, and writes the result to output_file. The sed command uses the :a;N;$!ba loop to read the entire file and the s/
//g command to delete all newline characters.

Here's an example of using sed to remove line endings from a file

$ cat input_file
Line 1
Line 2
Line 3

$ sed ':a;N;$!ba;s/
//g' input_file > output_file

$ cat output_file
Line 1Line 2Line 3

As you can see, the line endings in the input_file have been removed and the resulting text is now a single line in the output_file.

Removing Line Endings Using awk Command

The awk command is a powerful utility for processing text files. It can be used to delete or replace specific patterns in a file. To remove line endings from a file using awk, use the following command

awk '{printf("%s", $0)}' input_file > output_file

This command reads the input_file, removes all newline characters, and writes the result to output_file. The awk command reads each line of the input file and prints it to the output file using the printf function. The %s format specifier tells printf to treat the input as a string, and by omitting the newline character, awk prints the output without line endings.

Here's an example of using awk to remove line endings from a file

$ cat input_file
Line 1
Line 2
Line 3

$ awk '{printf("%s", $0)}' input_file > output_file

$ cat output_file
Line 1Line 2Line 3

As you can see, the line endings in the input_file have been removed and the resulting text is now a single line in the output_file.

Alternative Methods

You can also use the paste command with the -s option to join lines without separators

paste -s -d '' input_file > output_file

Another approach is using cat with xargs

cat input_file | xargs echo -n > output_file

Comparison of Methods

Conclusion

In this article, we explored how to remove line endings from a file on Linux using various command-line tools including tr, sed, awk, and paste. Each tool has its strengths tr is fastest for simple deletion, while sed and awk offer more flexibility for complex text processing. Choose the method that best fits your specific requirements and performance needs.